1. Technical Field
The present invention relates to a chaotropic agent, a reagent, a reagent kit, and an isolation method. More particularly, the present invention relates to a chaotropic agent, a reagent, a reagent kit, and a method for isolating a nucleic acid.
2. Description of Related Art
Conventionally, a nucleic acid is isolated from a nucleic acid-containing sample and purified by denaturing the protein and other substances in the sample using an organic solvent such as phenol and chloroform, and then performing centrifugation so that the denatured protein and substances are separated from the nucleic acid. However, as both phenol and chloroform are highly corrosive, highly volatile, and highly toxic, the aforesaid operation must be conducted with great care; otherwise, the operator is very likely to be injured. In addition, the purification process of this conventional method is time-consuming and therefore poses difficulties in commercial use.
Currently, the nucleic acid isolation methods used in commercial applications are mostly based on the patented particle isolation technique (U.S. Pat. No. 5,234,809) developed by Willem R. Boom et al. and assigned to Akzo Nobel N.V. In the afore-cited US patent, which is also known as the “Boom patent”, a nucleic acid is isolated from the non-nucleic acid substances in a sample by means of a chaotropic agent. The isolated nucleic acid binds to silica particles and is then eluted therefrom by a washing buffer so as to recover the nucleic acid. Nevertheless, the development trend of nucleic acid isolation techniques after the “Boom patent” is toward the use of magnetic particles, which are more effective in separating a nucleic acid from non-nucleic acid substances, as disclosed in U.S. Pat. No. 6,855,499, or toward further improvement of the composition of chaotropic agents.
For instance, U.S. Pat. No. 5,990,302 teaches a method for isolating a nucleic acid from non-nucleic acid substances by means of a guanidine salt-containing chaotropic agent and a nucleic acid-binding carrier. However, effective isolation cannot be achieved unless the proportion of the guanidine salt with respect to the solvents used is properly controlled. Moreover, as the manufacture of the guanidine salt is complicated and requires a separate production line, the guanidine salt-containing chaotropic agent may be difficult to prepare in practice.
Hence, the development of a chaotropic agent that features effective nucleic acid isolation, safe operation, convenient use, and easy manufacture and of a reagent kit containing such a chaotropic agent remains a problem to be solved.